[wp-hackers] Shortcode embedded within shortcode -- is it possible?

[Claude Needham]

The real world problem is a need to use aws s3 signed urls with
existing flowplayer plugin.

I offered code to flowplayer that would allow them to transparently
handle the s3 signed urls, but since there is still only a small
community of folks with a need for this feature, they were
understandably hesitant to take new code under their wing.

So my need is to find a way to dynamically refactor the video url at
runtime (during each page view). This is because the signed urls
typically have a 60 minutes lifetime.

I tried just putting a shortcode inside the other shortcode.
[FLOWPLAYER=http://domain.com/splash.jpg|[s3signedlink
url=https://s3.amazonaws.com/mybucket/myvideo.mp4],600,450]

That was a fail. Worth a try. But, at the time did not work for me. I
don't know php well enough yet to determine if the core shortcode
handler can deal with inline shortcodes within other shortcodes.

The note in wp-includes/shortcodes.php seems to indicate that the
simplistic approach will not work.

13	 * Shortcode tags support attributes and enclosed content, but does
not entirely
14	 * support inline shortcodes in other shortcodes. You will have to call the
15	 * shortcode parser in your function to account for that.
17	 * {@internal
18	 * Please be aware that the above note was made during the beta of
WordPress 2.6
19	 * and in the future may not be accurate. Please update the note
when it is no
20	 * longer the case.}}

So I'm looking for a clue on how to approach this. I'm a bit new to
php and much of the codex assumes more than the sparse background I
have currently.

Perhaps there is a hook or filter I can use that would allow me to get
at the video url in the flowplayer shortcode before it is processed.

Thanks for any hints.

Regards,
Claude Needham